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Molecular structure of human synaptonemal complex protein SYCE1

DOI: 10.1007/s00412-018-00688-z DOI Help

Authors: Orla M. Dunne (Newcastle University) , Owen R. Davies (Newcastle University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Chromosoma , VOL 14

State: Published (Approved)
Published: January 2019
Diamond Proposal Number(s): 15580 , 15836 , 15897

Open Access Open Access

Abstract: The reduction in chromosome number during meiosis is essential for the production of haploid germ cells and thereby fertility. To achieve this, homologous chromosomes are first synapsed together by a protein assembly, the synaptonemal complex (SC), which permits genetic exchange by crossing over and the subsequent accurate segregation of homologues. The mammalian SC is formed of a zipper-like array of SYCP1 molecules that bind together homologous chromosomes through self-assembly in the midline that is structurally supported by the central element. The SC central element contains five proteins—SYCE1, SYCE3, SIX6OS1, and SYCE2-TEX12—that permit SYCP1 assembly to extend along the chromosome length to achieve full synapsis. Here, we report the structure of human SYCE1 through solution biophysical methods including multi-angle light scattering and small-angle X-ray scattering. The structural core of SYCE1 is formed by amino acids 25–179, within the N-terminal half of the protein, which mediates SYCE1 dimerization. This α-helical core adopts a curved coiled-coil structure of 20-nm length in which the two chains are arranged in an anti-parallel configuration. This structure is retained within full-length SYCE1, in which long C-termini adopt extended conformations to achieve an elongated molecule of over 50 nm in length. The SYCE1 structure is compatible with it functioning as a physical strut that tethers other components to achieve structural stability of the SC central element.

Journal Keywords: Meiosis; Chromosome structure; Double-strand break; Chiasmata; Synaptonemal complex; Central element; SYCE1; Small-angle X-ray scattering; Biophysics

Subject Areas: Biology and Bio-materials


Instruments: B21-High Throughput SAXS